Carletta has $15,500 to invest. As her financial consultant, you recommend that she invest in Treasury Bills that yield 5%, Treasury Bonds that yield 6%, and corporate bonds that yield 7%, Carletta wants to have an annual income of $900, and the amount invested in corporate bonds must be half that invested in Treasury Bills. Find the amount she should place in each investment.

Carletta should invest $_____?_____ in Treasury Bills, $______?______ in Treasury Bonds, and $_______?_____ in corporate bonds to attain $900 annual income.